Single-leaf spring clamp



Jun 23, v1953 R. B. BURTON I 2,643,111

siNGLE-LEAF SPRING CLAMP Filed July 29, 1948 Patented June 23, 1953 UNITED sTATEs PATENT OFFICE SINGLE-LEAF SPRING CLAMP Robert B. Burton, Detroit, Mich., assignor to Gen eral Motors Corporation,y Detroit, Mich., a corporation of Delaware v Applioaiion July 29, 194s, serial No. 41,312

8 Claims. (Cl. 267-52) l 2 For road gear suspension of motor vehicles it dergo greatest tension and compression stress and has been proposed to employ a flexible spring the central bers will be stressed the least. That consisting of only a single' metal leaf instead of is with the conventional semielliptic spring arthe familiar multi-leaf or spring leaf pack berangement and upon load deflection the upperiWeen the Spllng and unSlJIllng paltS- In genmost bers are stretched and the lowermost fibers eral the installation of a single leaf spring may are compressed and in each instance the extent follow arrangements heretofore commonly used of stress decreases from maximum at opposite for multi-leaf springs, as in the conventional surfaces to zero near the center and the ideal Semiellintie Spring mounting @OnStIuction wherepositioning of the dimple formations is in the in pivotal joints connect opposite ends of the m region of zero stress. Also the dimples prefspring with the body or body supported chassis erably should be about midway of the length of and a xed connection joins an intermediate the clamping plates 'between which the spring portion of the spring rigidly With the SJXle. The leaf is held and which in a sense constitutes an pivotal end joints may be aiforded easily through axis about which the leaf portions which exeyes `curled in the opposite terminals of the J tend oppositely therefrom bend relative to one spring blade but the intermediate clamping conanother under axle torque and other forces.

nection between the single leaf and the axle has A more detailed description of the structure for proven to be of critical importance because of clamping a single leaf spring to an axle without the concentration of stress and the difficulties of stress concentration in the spring will be given breakage in the region of critical stress. Thus "lo in connection with the accompanying drawing With e multiple leef Spring wherein individual wherein Figure 1 is an elevation showing a load leaf breakage is unlikely to be of serious consesupporting spring between the chassis and axle; quence holes may be pierced in all the spring Figure 2 is a central longitudinal section of the leaves to receive fastening bolts but with a load n Vclamped plates in gripping and locating relation supporting spring consisting of only a single leaf '1 tothe axle attaching portion of the leafA spring similar bolt receiving openings entirelythrough intermediate its length; Figures 3 and 4 are the thickness of the leaf introduces weakness to transverse sections on lines 3 3' and 4 4, releetllle ai e niece Where great Strength and respectively, of Figure 2 but show the relation of sistance is most needed. l the parts prior to the application of clamping To reduce liability of breakage and remove hin- 3e pressure on the plates; Figure 5 corresponds to drances to adoptiOn 0f Single leef Springs it is Figure 3 except thatthe clamped plates have been here proposed to provide an improved Spring leaf drawn together in nal assembly relation and clamping arrangement which securely locates the Figure 6 is a perspective view to illustrate in axle and spring and effectively distributes load greater detail the spring embracing collar which transference without strength destroying formakeys together the clamping plates and the spring tions in the thickened flexible leaf. For a secure blade.

attachment without the additional expense and As seen in Figure 1 the opposite terminal eyes difficulties of specially forming a spring blade with on the spring blade I are pivotally joined to the integral anchorage projections there is here inchassis ll, one by a hinge pin bracket I2 and the volved a simple spring leaf which can be made ai) other by a swinging shackle I3, and the interaceerding t0 COIlVentiOnel leef Spring manufacmediate portion of the blade extends under and infine procedure but having dimple formel/lens is fixed to the axle le by U-bolts on each side, or small depressions in the side edge faces thereone of which is Shown at l5 in Straddhng re1a 0f S0 as t0 lie in the neutral plane or aXis of tion to the axle with adjustable retainer nuts on spring leaf nexure and to receive in keying relafifi the lower ends of the pins to engage the usual tOn COlTeSiJOnding pimples or prOl'eCtiOnS on e type of pressure plate Iii for cooperation with an spring encircling collar which itself is pocketed agie chair l1 in holding a pair of clamp plates against relative displacement within a Ypair of Iii- I8 which are of substantially U-shape in clamp plates fastened to the axle in load distransverse section and are fitted in opposing retributing and transferring relation over a fairly 5U lation to the spring leaf to box the same therein. large area of the adjoining spring leaf surface. v At opposite ends the clamp plates I8 have out- Gf important significance is the location of the turned flanges or abutment ears I9 to seat against dimples in the region of minimum stress concenthe ends of the pressure plate I6 and the axle tration. With respect to leaf thickness the fibers chair il respectively and thereby preclude relaclosest to the upper and lower surfaces will untive longitudinal displacement. In addition these ears I9 may flt into grooves formed in ends of either or both the axle chair I1 and the pressure plate IB to provide positive lateral alignment. Both clamp plates have a central transverse slot or opening to form pockets or keyways to receive protuberances or centrally thickened portions on the top and bottom of a collar or spring embracing strap or clip member shown as consisting of a pair of identical internested U-shaped clips 2 I-2 I. As shown each plate I8 is interiorly lined by a pair of channels 22-22 extending from adjacent the outturned end flanges I9 to the central slot 2|) With their adjacent ends in line with the slot edges to assist in providing abutment shoulders for the clips 2|. Preferably the liners 22 are welded in place as a one-piece unit with the respective plates I8. Optionally the plates IS may be so made and used as to eliminate the separate formation and attachment of channel liners.

Each clip 2| is made from strip stock cut to length with metal removed at opposite ends so as to form a rectangular slot 23 at one end and a terminal tongue 24 at the other end of reduced width corresponding substantially to the width of the slot 23 so as eventually to fit therein. Intermediate its ends the strip is struck with a rounded nosed tool to deform the metal and provide a concavo-convex pimple or bump 25 of spherical radius or of tapering depth. The spherical shape is easy to make and perhaps is stronger than a tapered cone shape but any equivalent tapered formation would serve the desired purpose and to which reference will -be made later. The strip is also bent to U-shape with the bump 25 centrally located and facing inwardly in the base thereof and the tongue 24 is bent back upon itself first to substantially V-shape, as shown by broken lines in Figure 6, and later into flattened relation, as in Figures 3 and 5. A pair of clips 2| are then applied from the opposite edges of the spring leaf IB, which in its manufacture has been dented or formed with dimples corresponding in shape with the convex surface of the pimple 25. The location of the dimples in the spring side edges is such that they lie in the region of the neutral axis of the spring leaf with reference especially to their apices or points of greatest depth. Thus when the convex depressions are seated Within the concave dimples the parts will be keyed together against longitudinal displacement without the need for removing metal from the spring in a manner which would be likely to weaken the spring in a region of critical stress. By reversing the clips in relation to one another their slotted ends 23 `can be caused to ride over and into latching relation with the reversely bent tongues 24. This can best be done when the tongues are in the broken line V-shape of Figure 6 so that When each tongue is nally flattened its end bears tightly against the adjacent end of the companion clip and both clips are drawn into snug bracelet relation with the spring and secure internested relation with each other.

To cushion impact from flying stones kicked up upon vehicle operation and otherwise minimize scratches and corrosion which might lead ultimately to blade fracture a protective covering 26 of rubber or the like completely encases the spring leaf from end to end and is molded in place or otherwise enveloped on the spring after the clips 2| are applied. separators 2l of sheet packing material are interposed between the rubber coating and the clamping plates I8. When the clamp plates are first applied but before the adjusting nuts on the U-bolts I5 are drawn up the uncompressed or free thickness of the rubber coating holds the clamp plates slightly spaced apart a desired predetermined distance as can be seen in Figures 3 and 4. The given spaced apart relation of the clamp plates governs the extent to which the nuts can be tightened, the limit being established bythe abutment of the clamp plates, as seen in Figure 5. The clamping pressure squeezes the rubber and insures a good frictional hold between the parts while also cushioning and insulating excessive transmission of axle torque and road shock into the spring and through the spring to the chassis. It will be noted further that the squeezing pressure on the rubber causes it to crowd into and more completely fill up the exterior concavities afforded by the bumps 25 and effectively back up these deformations to insure their interlocking retention within the dimples at the neutral axis of the spring. Obviously, the advantages of the rubber lining may be had with rubber pads and without extending the covering over the Whole of the spring as a complete enclosure therefor.

I claim:

1. In a vehicle having sprung and unsprung parts, a single leaf spring through which the load is transferred between said parts, spring end connecting means joining the spring to one of said parts and a spring intermediate connection with the other part comprising dimples in opposite side faces of said single leaf spring occupying the zone of the neutral axis of bending, a collar surrounding said leaf spring and carrying internal projections fitted in interlocking relation to said dimples, a protective covering of elastic deformable material enveloping said spring leaf and said collar, a pair of clamp plates fitted to the-'top and bottom of the spring leaf and about said covering and having recessed portions to receive and interlock with portions of said collar, and fastening means anchoring said other part to the clamp plates and being arranged to press the clamp plates toward one another for squeezing the covering engaged thereby and eiecting tighter interlock with said collar and betweensaid collar projections and the side face dimples in the spring leaf.

2. In combination, a single leaf spring having a dimple in its side on the neutral axis of the spring, a pair of U-shaped fittings embracing the spring leaf in interlocked relation and having a projection in keyed relation to said dimple and clamp plates in interlocking engagement with said fittings.

3. In combination, a load supporting spring consisting of one leaf only, said spring having dimples in the side edge faces thereof, a pair of complementary U-shaped locating straps fitted together with the legs overlapping to form a leaf encompassing collar, the base of each strap having a pimple to seat in a corresponding dimple in the leaf, and one leg of each strap having a narrowed terminal reversely bent upon the strap and fitted in latching relation Within an opening in the other leg of its complemetal strap and a pair of clamp plates engaging top and bottom faces of said leaf in interlocking relation with said straps.

4. In combination, a load supporting spring consisting of only one leaf, said leaf having concavities in the edge faces thereof, a collar surrounding the leaf in the region of said concavities and having internal convexities fitted to the concavities of said leaf and also having external concavties, a lining of deformable material sur rounding said collar and filling said external concavities and a pair of clamp plates tted over the top and bottom of the leaf and lining with locating pockets in keying relation to said collar and arranged when drawn together under clamp ing pressure to crowd the lining into more secure confinement within said external concavities.

5. In a vehicle suspension or the like, a single spring leaf and a mounting connection at an intermediate portion in the length of the spring leaf, one edge of said spring leaf being provided with a depression spaced from the upper and lower surfaces thereof, a clip member engaging said intermediate portion of the spring leaf and provided with a projection extending into interlocking engagement with said depression, and clamp plates being iitted to the top and bottom of the spring leaf and about said clip member and provided with recesses adapted for interlocking engagement with portions of said clip member, for the purpose set forth.

6. A vehicle suspension or the like comprising, a single spring leaf, and a mounting connection therefor at an intermediate position in the length of the spring leaf including, a clip member engaging said intermediate portion of the spring leaf, a recess in one edge of said spring leaf lcated wholly within the boundaries thereof, a projection on said clip member having an interlocking engagement with said recess, relatively movable clamp members embracing said clip member and provided With means effecting an interlocking engagement with said clip member, and a clamp bolt connection extending about said spring leaf, said clip member and said clamp members, said clamp bolt connection being contractable upon said clamp members to hold said clamp members in said engagement with said clip member.

7. For the anchorage of a single spring leaf to a joining element and in which the spring leaf has tapering depressions wholly formed within and midway between the opposite edge faces of said spring leaf, and comprising a pair of interlocking clip members encircling the region of the spring leaf having said depressions therein and having key elements seated in said depressions to interlock said spring leaf and said clip members, and clamp members embracing said clip members and having means clamping said clamp members in interlocking engagement with said clip members.

8. In a vehicle suspension or the like, a single spring leaf having a dimple formedy in a side edge face thereof, a clip member closelyT encircling an intermediate portion of said spring leaf and having a projection extending therefrom and into said dimple to interlock said clip member and said spring leaf, and clamp plates gripping said spring leaf and abutting a portion of said clip member, said clip member being positioned between said clamp plates to key said clamp plates and said spring leaf against endwise displacement.

ROBERT B. BURTON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 296,994 Morris Apr. 15, 1884 901,162 Fay et al. Oct. 13, 1908 2,052,930 Laursen Sept. 1, 1936 2,123,772 Eisenhauer July 12, 1938 2,211,647 y Collier Aug. 13, 1940 2,533,511 Rowland Dec. 12, 1950 FOREIGN PATENTS Number Country Date 526,407 Great Britain Sept. 17, 1940 664,516 France Apr. 23, 1929 

